Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 71b Filter Condenser Bank Question
#6

Also am yet again puzzled, and still a novice at radio restoration and troubleshooting. I tested all the tubes, this model uses a 42 for audio output, the st type already in the chassis tested bad and quite weak. I only have several Globe type 42's in my stock. It tested good, and I will use it as a replacement for the initial power-up. I first put the set in series with a dim bulb tester just to see if the transformer has any shorts and it didn't as I expected. I did tune the dial to see if I would get anything but didn't, most likely because of the voltage limiter caused by the bulb. I then did a slow power-up with the power cord plugged into a variac. The end result was; all tubes had a glow, there was also a 60 cycle hum heard when I increased the volume pot, it went away when the volume was at zero.

The most concerning thing is that I did not get any other type of noise out the set for those 3 minutes. I am hoping that a full recap of the electrolytics and caps will fix the problem, this is my first encounter with no noise from the speaker on an initial power up.

I also noticed the mica trimmers that come off each section of the three gang available capacitor are still present, but the second one is chipped a bit and the third one is bent up on one side as in the picture. I know there could be quite a few factors contributing but, could this of caused the silence in the set?


Attached Files Image(s)
   


Messages In This Thread
RE: Philco 71b Filter Condenser Bank Question - by Philco281989 - 05-02-2013, 09:09 PM
Help on checking the coils - by Philco281989 - 05-03-2013, 07:04 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Refinishing Ideas
Hi Poulsbobl, I think that you could get away with it.  In the Philco Library, there is a parts listand specs for sp...MrFixr55 — 11:54 PM
Philco 46-480 Electronic Restoration
The sleeving for the transformer arrived early, so I went ahead and finished reassembling. The chassis looks far better ...jrblasde — 10:15 PM
Philco 610B oscillator wiring
I don't know what you are referring to when you say "tube cathode ground". Ground is a connection to the chass...RodB — 05:56 PM
Zenith H725
Good points, Arran. I haven't encountered this problem with any other radio (all earlier vintages), so am learning here....EdHolland — 05:32 PM
Zenith H725
Ed; One thing that I will say about these is that Brand Z was considerate enough to make these mica caps easily acces...Arran — 02:34 PM
Philco 610B oscillator wiring
Do you know what run # your chassis is? It took me a while to find what you were basing updates/modification on as I did...Radioroslyn — 07:34 AM
Need to purchase some accessories for restoration of my Old Philco Radio
COLLEAGUES, Thank you all for such good and important suggestions as how to find good replacement parts. I will go fo...palonso — 07:05 AM
Zenith H725
Here's what the inside of AM IFT2 looked like, and the other pic shows the discs I made to take place of the mica and ke...EdHolland — 07:40 PM
Zenith H725
IF2 will need replacement caps. The arcing was severe enough that the mica is pitted and holed where the HT flashed over...EdHolland — 04:04 PM
My Philco 37-116 Restore
Measuring from center tap like the tube voltages show. Cap 127 is isolated from ground. Cap 127 shown in upper left of p...dconant — 08:05 AM

[-]
Who's Online
There are currently no members online.

>